Non-circular resection device and endoscope

ABSTRACT

A proximal housing for a full-thickness resection device (FTRD) is provided with a plurality of chambers through which fasteners are introduced into a portion of tissue to be resected. The proximal housing has a noncircular cut-out opposite the plurality of chambers to receive a noncircular endoscope. The proximal housing also is provided with a resection cavity into which the tissue to be resected is to be received. In addition, shaft openings are provided through which mounting shafts may be inserted. A noncircular endoscope is also disclosed for insertion into the cut-out whereby the endoscope has passages to house the functions of remote viewing, illumination, insufflation and irrigation.

The present application is a continuation of application Ser. No.09/906,142 filed Jul. 17, 2001, now U.S. Pat. No. 6,629,630“Non-Circular Resection Device and Endoscope” which is acontinuation-in-part of U.S. application Ser. No. 09/813,944, filed Mar.22, 2001 (issued as U.S. Pat. No. 6,343,731) which is a continuation ofU.S. application Ser. No. 09/694,894 (“the '894 application”), filedOct. 25, 2000 (issued as U.S. Pat. No. 6,241,140). The '894 applicationis a continuation of application Ser. No. 09/316,674, filed May 21, 1999(issued as U.S. Pat. No. 6,179,195), which application is a division ofapplication Ser. No. 09/100,393, filed Jun. 19, 1998 (issued as U.S.Pat. No. 6,126,058).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a full-thickness resectiondevice (FTRD) for performing localized resections of lesions in tubularorgans, particularly the colon. The present invention has particularapplication to transanal and transoral surgical procedures, although itis not limited thereto.

2. Description of the Related Art

A resection procedure involves excising a portion of an organ,approximating the surrounding tissue together to close up the holecreated by the excision, and removing the excess tissue. Variousconventional devices and procedures are available for resectioninglesions in tubular organs.

For example, several known resection devices and procedures require atleast one incision in an area near the portion of the organ to beexcised for access to the lesion or treatment site (because, forexample, the resectioning device may lack steering and/or viewingcapabilities). Thus, the incision is required to allow the physician toaccess the organ section to be excised and guide the device to thatsection. Alternatively, when the organ section to be excised is beyondthe reach of the surgical device, or the surgical device is not flexibleenough to wind through the organ to the site to be excised, an incisionwill be required to position the device for the procedure. Of course,these incisions are painful and may involve a partial or entire loss ofmobility while recuperating from the incision, in addition to recoveringfrom the tubular resectioning procedure itself. In addition, the timerequired to recover from such a procedure is often longer than forprocedures which do not require incisions.

One type of conventional resection procedure utilizes a circularstapling instrument in which a tubular section of a tubular organ isexcised, resulting in the tubular organ being separated into a firstsegment and a second segment. The end sections of the first and secondsegments are then individually tied in a purse-string fashion,approximated, stapled, and the “purse-stringed” end sections are thencut off. In this full circle resectioning procedure, at least oneseparate invasive incision must be made near the section to be excisedin order to cut and individually tie the separate end sections of theorgan. Also, a separate incision is necessary to place one part of theresectioning device in the first segment and a corresponding second partof the device in the second segment so that the device can then bringthe first and second segments together to re-attach the organ sectionsback together. A first of these separate parts may generally include astaple firing mechanism while the second part includes an anvil forforming the staples. Thus, this type of resectioning procedure involvesthe drawbacks mentioned above in regard to procedures requiring invasiveincisions. In addition, the separation of the organ into two segmentscreates the risk of spillage of non-sterile bowel contents into thesterile body cavity, which can cause severe infection and possiblydeath.

An alternative resectioning device includes a stapling and cuttingassembly on a shaft which can be bent or formed into a desired shape andthen inserted into a patient's body cavity. Once the shaft has been bentinto the desired shape, the rigidity of the shaft ensures that thatshape is maintained throughout the operation. This arrangement limitsthe effective operating range of the device as the bending of the shaftinto the desired shape before insertion and the rigidity of the shaftonce bent require the physician to ascertain the location of the organsection to be removed before insertion, and deform the shaftaccordingly. Furthermore, the rigidity of the shaft makes it difficultto reach remote areas in the organ—particularly those areas which mustbe reached by a winding and/or circuitous route (e.g., sigmoid colon).Thus, an incision may be required near the organ section to be excisedin order to position the device at the organ section to be excised.

Currently such FTRD's incorporate standard endoscopes available fromvarious manufacturers. These standard endoscopes are circular in shape,and while a circular shape is desirable in many conventionalapplications where the endoscope is used independently, with FTRD's, acircular endoscope, for example, takes up significant space in the bodylumen. This can result in a sample having a smaller size than desired. Acircular endoscope also may not have sufficient flexibility to bend to adesired location.

SUMMARY OF THE INVENTION

In accordance with the invention, a proximal housing for afull-thickness resection device (FTRD) is provided with a plurality ofchambers through which fasteners are introduced into a portion of tissueto be resected. The proximal housing has a noncircular cut-out oppositethe plurality of chambers to receive a noncircular endoscope. Theproximal housing also is provided with a resection cavity into which thetissue to be resected is to be received. In addition, shaft openings areprovided through which mounting shafts may be inserted.

According to another aspect of the invention, the plurality of chambersis configured so as to provide a substantially elliptical fastenerpattern.

According to yet another aspect of the invention, the fasteners used arestaples.

According to another aspect of the invention, a noncircular endoscope isalso disclosed that is substantially the same shape as the cut-out forinsertion into the cut-out whereby the endoscope has passages to housethe functions of remote viewing, lighting, insufflation and irrigation.

According to another aspect of the invention, the noncircular endoscopeis elliptical in shape.

Additional objects and advantages of the invention will be set forth inpart in the description which follows, and in part will be obvious fromthe description, or may be learned by practice of the invention. Theobjects and advantages of the invention will be realized and attained bymeans of the elements and combinations particularly pointed out in theappended claims. Both the foregoing general description and thefollowing detailed description are exemplary and explanatory only andare not restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate one embodiment of the inventionand together with the description, serve to explain the principles ofthe invention.

FIG. 1 is a perspective view showing a full-thickness resection deviceaccording to an embodiment of the present invention;

FIG. 2 is a perspective view showing the device of FIG. 1 mounted on anendoscope according to an embodiment of the present invention;

FIG. 3 is a perspective view showing the device of FIG. 1 with a graspermechanism extending therefrom;

FIG. 4 is a perspective view showing a drive mechanism of FIG. 1;

FIG. 5 is a perspective view showing the device of FIG. 1 with a taperedend for ease of insertion;

FIG. 6 is a cross-sectional view of a proximal housing of afull-thickness resection device, according to an embodiment of thepresent invention;

FIG. 7 is a cross-sectional view showing an endoscope to be used withthe device of FIG. 6.

DESCRIPTION OF THE EMBODIMENTS

The present invention is directed to a non-circular endoscope andcorresponding FTRD. These non-circular devices have numerous advantagesover existing circular devices. For example, the non-circular shapeallows the device to take up less space within the body lumen into whichit is being inserted. The non-circular endoscope also provides a moreefficient means of packaging the combination of the device andendoscope. The more efficient utilization of space enables a device thatcan capture larger specimen sizes than an equivalent circular endoscopewould permit. In addition, a non-circular endoscope for use with an FTRDmay be more flexible and therefore more easily bend forwards a desiredlocation, due, for example, to the smaller cross-sectional area of theendoscope. In preferred embodiments, the endoscope is shaped forparticular use in combination with devices that perform a full thicknessresection or similar procedure. In addition, the shape of a staplecartridge and anvil of the devices has a more elliptical, non-circularstaple pattern that also provides further advantages.

Reference will now be made in detail to the present embodiments of theinvention, examples of which is illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

As shown in FIGS. 1 and 2, an FTRD comprises a working head assembly 2which may be connected to a distal end 4 a of a sheath 4. The proximalend of the sheath 4 may be connected to a control handle 6. Inoperation, the entire apparatus is mounted onto an endoscope 8, having aproximal end 8 a and a distal end 8 b, by passing the endoscope 8through the control handle 6, the sheath 4, and the working headassembly 2, as shown in FIG. 2. The endoscope 8 is then inserted into abody orifice to locate a lesion in the tubular organ under visualobservation (usually while insufflating the organ). Once the lesion hasbeen located, the working head assembly 2 and the sheath 4 are slidablyadvanced along the endoscope 8 into the tubular organ until the workinghead assembly 2 is in a desired position adjacent to the lesion. Thoseskilled in the art will understand that in an alternative embodiment,the working head assembly 2 may also be detachably coupled to a distalend of the endoscope 8, and the entire arrangement may then be insertedinto the body orifice under visual observation.

As shown in FIG. 1, the working head assembly 2 comprises an anvilmember 10 coupled to a distal end 12 a of a proximal housing 12. Theanvil member 10 has a substantially crescent-shaped cross-section (i.e.,the outer edge 18 of the anvil member 10 substantially forms a portionof a first ellipse with a second smaller elliptical cut-out 13 formedwithin the first ellipse) with a distal face 16 and a larger proximalface opposite the distal face. The cut-out 13 of the anvil member 10 isincluded to allow the endoscope 8 to be slid through the entire workinghead assembly 2 so that the endoscope 8 may be advanced into the bodypassage allowing the working head assembly 2 to later be advanced intothe body to the lesion. In addition, the cut-out 13 also providesforward vision via the endoscope 8. Thus, any shape of the cut-out 13may be selected which is large enough to accommodate the endoscope 8,with a larger cut-out providing a larger field of vision. An outersurface 18 of the anvil member 10 extends substantially parallel to acentral axis of the working head assembly 2 while the proximal anddistal faces of the anvil member 10 extend in planes substantiallyperpendicular to the central axis. The outer surface 18 is joined to thedistal face 16 by a tapered portion 5.

As shown in FIG. 3, the proximal face of the anvil member 10 includes afirst cavity 37 and a rim 41 encircling the first cavity 37. A pluralityof staple-forming grooves 19 are arranged in two offset rows on the rim41 of the anvil member 10 and an elliptical guiding slit 21 extendsradially within the rows of grooves 19. The rim 41 protrudes from theremainder of the proximal face so that a shallow cavity is formed on theproximal face.

The anvil member 10 is coupled to the proximal housing 12 by means oftwo mounting shafts 20 a and 20 b, which may be substantiallycylindrical. Each mounting shaft 20 a, 20 b is coupled to the proximalface 14 of the anvil member 10 on a respective one of two horns 22 a, 22b formed by the crescent-shaped anvil member 10. Although the anvilmember 10 is shown fixedly coupled to the mounting shafts 20 a, 20 b,those skilled in the art will understand that the anvil member 10 mayalso be pivotally coupled to the mounting shafts 20 a, 20 b in order toprovide a greater field of vision through the endoscope 8, as shown inFIG. 3. In this pivoted-type arrangement, the anvil member 10 is angledin a first configuration so that the horns 22 a, 22 b are closer to thedistal end 12 a of the proximal housing than the rest of the anvilmember 10. Then, as the anvil member 10 is drawn towards the distal end12 a of the proximal housing 12, the anvil member 10 would be pressedagainst the distal end 12 a beginning with the horns 22 a, 22 b, whichwould cause the anvil member 10 to pivot until the proximal face 14 ofthe anvil member 10 is parallel to the distal end 12 a.

As shown in FIG. 1, the mounting shafts 20 a, 20 b are slidably receivedin mounting holes 26 a, 26 b, which have a size and shape substantiallycorresponding to the size and shape of the mounting shafts 20 a, 20 band which run axially through the proximal housing 12. The mountingshafts 20 a, 20 b are preferably movable axially proximally and distallywithin the mounting holes 26 a, 26 b between a proximal most position inwhich a tissue gripping gap of a first predetermined width is formedbetween the rim 41 and the distal end 12 a of the proximal housing 12,and a distal most position in which a tissue receiving gap of a largersecond predetermined width is formed between the rim 41 and the distalend 12 a of the proximal housing 12. The second predetermined widthshould preferably be more than twice the thickness of a wall of theorgan being resectioned so that a section of the tubular organ may bepulled into a resectioning position between the anvil member 10 and theproximal housing 12.

As shown in FIG. 4, the proximal end of at least one of the mountingshafts 20 a and 20 b is coupled to a drive mechanism 92 provided withinthe proximal housing 12. The drive mechanism 92 is composed of a yoke 93and a drive shaft 95. The yoke 93 is slidably received within theproximal housing 12 for longitudinal movement along the axis of theproximal housing 12 so that, when the anvil member 10 is in the proximalmost position, the yoke 93 is in a corresponding proximal most positionand, when the anvil member is in the distal most position, the yoke 93is in a corresponding distal most position.

The yoke 93 may be substantially elliptical with a substantiallyrectangular cross-section. Although the ellipse formed by the yoke 93 inFIG. 4 forms substantially a quarter arc of a ellipse, the yoke 93 mayform a larger ellipse based upon the interior accommodations of theproximal housing 12 and the position of the mounting shafts 20 a, 20 b.The mounting shaft 20 a may preferably be coupled to the yoke 93 at afirst end 93 a of the yoke 93, and the mounting shaft 20 b may becoupled at a second end 93 b of the yoke 93. A shaft hole 97, having adiameter substantially corresponding to a diameter of a complementarilythreaded distal end 95 a of the drive shaft 95, extends through the yoke93 at a point substantially midway between the first end 93 a and secondend 93 b. Thus, when the drive shaft 95 is rotated, the threaded distalend 95 a engages the shaft hole 97 to move the yoke 93 proximally ordistally (in dependence upon the direction of rotation of the driveshaft 95).

The distal end 95 a of the drive shaft 95 should preferably be threadedover a first section 95 t substantially corresponding in length to atleast the distance between the proximal and distal most yoke positions,while a remainder portion 95 r may have no threads thereon. The driveshaft 95 may have an increased cross-section in the areas immediatelyadjacent to the threaded first section 95 t (proximally and/or distallyof section 95 t), thereby limiting the movement of the yoke 93 to thefirst section 95 t. Those skilled in the art will understand that thedrive shaft 95 is rotatably mounted within the proximal housing 12 sothat it may only rotated and may not move relative to the proximalhousing 12. The drive shaft 95 extends to a proximal end 95 b which iscoupled to a drive cable 90 which extends to the control handle 6through the sheath 4. The drive cable 90 may run axially along theperipheral interior of the sheath 4. Those skilled in the art willunderstand that the sheath 4 is torsionally stiff to resist the torqueforces from the drive cables rotating therein. However, the sheath 4 islongitudinally flexible to so that it may be slidably advanced along theendoscope 8, while minimizing interference with the operation of theendoscope 8 and trauma to surrounding tissue. The sheath 4 isconstructed similar to other known endoscope insertion tubes, which areflexible yet allow the transfer of forces to swivel the distal end ofthe endoscope 8 in multiple directions and the torqueable rotation ofthe endoscope.

In operation, the user advances the endoscope 8, with the working headassembly 2 received therearound, to a portion of tissue to beresectioned until the working head assembly 2 is in a desired positionadjacent to the tissue to be resectioned. The user may then apply aforce to the control handle 6 to rotate the drive cable 100, as seen inFIG. 4, which in turn rotates the drive shaft 95 to advance the yoke 93and the anvil member 10 distally away from the distal end 12 a of theproximal housing 12. As shown in FIG. 3 when the anvil member 10 hasreached the distal most position, a known grasping device 98 is advancedthrough the sheath 4 and through the working head assembly 2 to enterthe gap between the anvil member 10 and the distal end 12 a via one ofthe grasper holes 32 and 33. Although the device in FIG. 3 is shownusing a duodenoscope as the endoscope 8, those skilled in the art willunderstand that other types of endoscopes may also be used, such as, forexample, gastroscope, colonoscope, etc.

As shown in FIG. 1, at least the distal end 12 a of the proximal housing12 has a cross-section corresponding in size and shape to the proximalface 14 of the anvil member 10, including a cut-out 29 substantiallycorresponding in size and shape to the cutout 13 of anvil member 10. Thecut-out 29 is provided to receive the endoscope 8 therein and allow theproximal housing 12 to be slidably advanced along the endoscope 8. Ofcourse, those skilled in the art will understand that the shape of theouter surface of the working head assembly 2 may be selected in order toaccommodate various desired resectioning shapes, and the shape of theanvil member 10 may preferably be selected to form a continuous surfacewhen positioned adjacent to the proximal housing 12 to facilitateadvancing the working head assembly to into and removing it from, bodypassages. It is preferable that the working head assembly have a maximumdiameter at any point between 15 mm and 40 mm.

A tissue receiving cavity 30 is formed substantially centrally in thedistal end 12 a of the proximal housing 12 to facilitate the drawing ofsections of tubular organs into the gap between the anvil member 10 andthe distal end 12 a. Those skilled in the art will understand that thedepth of the cavity 30 may vary depending on the amount of tissue to bepulled into the cavity 30 and the size of the proximal housing 12. Twograsper holes 32 and 33 extend axially, preferably slightly off-centerfrom the longitudinal axis of the proximal housing 12. The grasper holes32 and 33 may each receive a grasping device 108 advanced from thecontrol handle 6, through the sheath 4, and through a respective one ofthe grasper holes 32 and 33.

In operation, either one or two grasping devices 98 may then be used topull a section of the tubular organ between the anvil member 10 and thedistal end 12 a of the proximal housing 12 and into the cavity 30. Athird grasping device 98 may also be inserted through the workingchannel of the endoscope 8 to provide another means of positioning theorgan section between the anvil member 10 and the proximal housing 12.Of course, those skilled in the art will understand that any desiredinstrument may be advanced to the gap between the anvil member 10 andthe distal end 12 a through any of the grasper holes 32, 33 and theworking channel of the endoscope 8.

A plurality of staple slits 34 are preferably disposed in two offsetsubstantially elliptical rows extending along the periphery of thedistal end 12 a of the proximal housing 12. The staple slits 34 extendfrom an area adjacent to the mounting shaft 26 a to an area adjacent tothe other mounting shaft 26 b. The plurality of staple slits 34 may bearranged so that when the anvil member 10 is in the proximal mostposition, each of the staple slits 34 is aligned with a correspondingone of the staple-forming grooves 19.

When the device is configured for operation, a plurality of staples isreceived within the working head assembly 2 with each of the staplesbeing aligned with a respective one of the staple slits 34. The staplesare then sequentially fired from the respective staple slits 34 by anactuating mechanism (not shown) disposed in the proximal housing 12.

A substantially elliptical blade slit 36 extends substantially radiallywithin the staple slits 34 so that, when the anvil is in the proximalmost position, the blade slit 36 is aligned with the guiding slit 21 onthe anvil member. As shown more clearly in FIG. 4, extensions 84 a and84 b of the blade slit 36 extend into blade housings 74 a and 74 b,respectively, which project distally from the distal end 12 a ofproximal housing 12. The blade housings 74 a and 74 b are preferablysituated so that when the anvil member 10 is in its proximal mostposition, the blade housings 74 a and 74 b contact portions 43 a and 43b of the rim 41 of the anvil member 10. The extension of the bladehousings 74 a and 74 b from the proximal housing 12 is preferablyselected so that when the blade housing devices 74 a and 74 b engage theremainder portions 43 a and 43 b of the rim 41 (thereby stopping aproximal movement of the anvil member 10 and defining the proximal mostposition thereof), a gap is formed between the anvil member 10 and thedistal end 12 a of a length sufficient to allow the anvil member 10 tosecurely hold a portion of the organ against the proximal housing 12without crushing and damaging the portion of the organ.

When positioned at one end of the blade slit 36 (i.e., in one of theextensions 84 a and 84 b), a cutting blade (not shown) is preferablycompletely enclosed within the respective one of the blade housingdevices 74 a and 74 b and the guiding slit 21, so that the cutting bladedoes not cut any tissue until the physician intentionally operates theblade. When the physician operates the blade, the blade is driven fromits initial position received within one of the extensions 84 a and 84 baround the blade slit with its cutting edge facing a direction ofmovement, until the blade is received into the other one of theextensions 84 a and 84 b. Thus, after a cutting operation has beenperformed, the blade is once again prevented from inadvertently injuringthe patient.

As can be seen in the prior art devices utilizing a circular endoscope,the endoscope occupies significant space within the FTRD and alsoencroaches upon the resection cavity. With the prior art devices, inorder to provide a cavity of the size necessary to perform the desiredsurgical procedure, the overall size of the FTRD must be made larger.

FIG. 6 shows a cross section of a proximal housing 112 of an FTRD, andis configured to receive a non-circular endoscope within cut-out 129.Proximal housing 112 also contains mounting holes 126 a and 126 b aswell as mounting shafts.

As can be seen, cut-out 129 does not extend into cavity 130 as much asin the prior art devices, thus allowing the overall size of proximalhousing 112 to be reduced. In addition, the elliptical shape of the headprovides a more desirable elliptically shaped staple pattern for thestaples ejected from chambers 134 than the partial circular pattern ofthe prior art devices.

Endoscope 108, as seen in FIG. 7, is an endoscope of the presentembodiment to fit within cut-out 129. Rather than using a standardcircular endoscope of the prior art devices that may provide morechambers than what is necessary for a full-thickness resectionprocedure, the current invention relates to an endoscope that providesonly what is needed for the desired procedure. Endoscope 108 can beprovided with as few as four chambers to house the functions used toperform this procedure: remote viewing, lighting, insufflation andirrigation.

According to the present embodiment, endoscope 108 has an ellipticalshape to fit within cut-out 129 of proximal housing 112. Those skilledin the art would understand that other noncircular shaped endoscopescould be utilized that provide the same low-profile shape that theelliptical shape provides. Provided within endoscope 108 are fivechambers 108 a-108 e. Chamber 108 c preferably houses the optics portionof the endoscope. Chambers 108 b and 108 d contain light sources toilluminate the area in which the procedure is to be performed. Chambers108 a and 108 e may provide the insufflation and irrigation functions ofthe endoscope, respectively, although one of ordinary skill in the artcould comprehend that these functions may be reversed. In operation anFTRD utilizing proximal housing 112 will function in the same manner asthe prior art FTRD's.

Other embodiments of the invention will be apparent to those skilled inthe art from consideration of the specification and practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only, with a true scope and spiritof the invention being indicated by the following claims.

What is claimed is:
 1. A system for endolumenally resecting afull-thickness portion of an organ comprising: a flexible endoscopehaving a substantially non-circular cross-section, the endoscopeincluding a plurality of chambers extending therein; a resection housingincluding a stapling mechanism and an anvil member moveable relative toone another between a tissue receiving position and a stapling positionand an endoscope receiving channel extending therethrough, wherein theanvil member is mounted to the housing so that an angle of the anvilmember relative to the stapling mechanism may be varied to alter a fieldof view of the endoscope when the endoscope is received within theendoscope receiving channel.
 2. The system according to claim 1, whereinthe plurality of chambers includes an insufflation chamber, anirrigation chamber, a lighting mechanism chamber and a viewing mechanismchamber.
 3. The system according to claim 1, wherein cross-sections ofthe endoscope receiving channel and the endoscope are substantiallynon-circular.
 4. The system according to claim 3, wherein thecross-sections of the endoscope receiving channel and the endoscope aresubstantially elliptical.
 5. The system according to claim 1, whereinthe stapling mechanism includes a plurality of staple firing chambersarranged around a periphery of the housing and wherein the anvil memberincludes a corresponding plurality of staple forming grooves arrangedaround a periphery thereof.
 6. The system according to claim 1, whereina cross-section of the housing is substantially elliptical.
 7. Thesystem according to claim 6, wherein the stapling mechanism includes aplurality of staple firing chambers arranged around a periphery of thehousing and wherein the anvil member includes a corresponding pluralityof staple forming grooves arranged around a periphery thereof.
 8. Thesystem according to claim 1, wherein the anvil member is coupled to thestapling mechanism by at least one mounting member slidably mountedwithin the housing and wherein the anvil member is pivotally mounted ona distal end of the at least one mounting member.
 9. A resection housingfor endolumenally resecting a full-thickness portion of tissuecomprising: a stapling mechanism including a substantially non-circularendoscope receiving channel extending therethrough; and an anvil membermoveably mounted to the stapling mechanism for movement relative theretobetween a tissue receiving position and a stapling position, the anvilmember including an endoscope viewing opening therethrough, wherein theanvil member is mounted to the stapling mechanism so that an angle ofthe anvil member relative to the stapling mechanism may be varied toalter a field of view through the endoscope viewing opening of anendoscope received within the endoscope receiving channel.
 10. Thehousing according to claim 9, wherein the anvil member is substantiallycrescent shaped with an interior of the crescent forming the endoscopeviewing opening, wherein the anvil member is pivotally coupled to atleast one mounting member slidably received within the staplingmechanism.
 11. The housing according to claim 10, wherein the staplingmechanism includes a plurality of staple firing channels opening to adistal face thereof and wherein the anvil member includes acorresponding plurality of staple forming grooves formed on a proximalface thereof so that, when in the stapling position, each of the staplefiring channels faces a corresponding one of the staple forming groovesacross a stapling gap.
 12. The housing according to claim 10, wherein,when in the stapling position, the proximal face of the anvil member andthe distal face of the stapling mechanism are substantially parallel toone another and wherein the anvil may be pivotted about the at least onemounting member to a viewing position in which a portion of a peripheryof the endoscope viewing opening is moved toward the distal face of thestapling mechanism relative to a distal end of the at least one mountingmember to increase a field of view therethrough.